Effect of guanidinium chloride concentration on the renaturation of denatured lysozyme

The effect of guanidinium chloride (GdmCl) on the renaturation of denatured-reduced chicken egg white lysozyme was studied. It was found that the renaturation yield was significantly related to the GdmCl concentration, that is, the GdmCl concentration required to obtain a high renaturation yield increased with the increase of the denatured lysozyme concentration. When denatured lysozyme concentrations were lower than 0.21 g/L, the presence of 0.7 mol/L GdmCl resulted in the complete renaturation of lysozyme, while higher GdmCl concentration, i.e., 1.0-1.5 mol/L, was needed to yield more than 95 % renaturation of 0.6-1.05 g/L of the denatured lysozyme. In addition, lysozyme renaturation rate decreased with increasing GdmCl concentration. Therefore, it is considered that optimizing GdmCl concentration is the key step to enhance the renaturation yield of denatured proteins.